Evaporator



F. l.. BocK June l5, 1943.

EVAPORATOR Filed Feb. '7, 1942 Patented June 15, 1943 Application February 7, 1942, Serial No. 429,907

7 Claims.

This invention relates to evaporators, and with regard to certain more specific features, to evaporators for use as unit-type humidiiiers.

Among the several objects of the invention may be noted .the provision of a compact, highcapacity evaporator presenting a minimum impedance to air flow in which internal loss of energy is minimized; the provision of apparatus of the class described in which little or no moisture is entrained as liquid at the outlet although a high air capacity at high humidity is produced; and the provision 'of apparatus of this class which is economical, light enough for ceiling suspension, and in which the parts are easily accessible for adjustment and repair. Other objects will be in part obvious and in part pointed out hereinafter.

The invention accordingly comprises the elements and combinations of elements, features of construction, and arrangements of parts which will be exemplified in the structures hereinafter described,'andthe scope of the application of which will be indicated in the following claims.

In the accompanying drawing, in which is illustrated one of various possible embodiments of the invention,

Fig. 1 is a rear elevation showing the device suspended;

Fig. 2 is a right-side elevation of Fig. 1;

Fig. 3 is an enlarged horizontal section taken on line 3-3 of Fig. 2;

Fig. 4 is a detail of the construction of the base of a conical mat holder; and,

Fig. 5 is an enlarged detail of the construction of the apex of said conical member.

Similar reference characters indicate corresponding parts throughout the several views of the drawing.

Referring to the drawing, numeral I indicates a cylindric closure or air inlet member which is joined by means of a frusto-conical reducing p0rtion 3 to a cylindric air outlet nozzle 5. The parts I, 3 and 5 are continuous but not necessarily of one piece and preferably are formed of sheet metal of suitable gage for stiffness. Hangers 1 serve to support the device by suspension from a ceiling or the like with its axis substantially horizontal. The air stream enters inlet 43 of cylinder I and leaves the outlet 65 of nozzle 5.

Numeral 9 in general indicates a conical matholding member composed of an inner conical coarse-mesh screen II and an outer coarse-mesh conical screen I3, between which is va, conical Cil mat of absorbent fibrous material I5, such as excelsior or sisal. This material absorbs moisture, carrying it upon the surfaces of its bres for evaporation. Other similar absorbent fibrous materials may be used, but those mentioned have been found to be satisfactory. The screens II and I3 are of the order of one-inch mesh, for example. They are relatively stii and rigid. Their meshes may be of any shape but a square mesh is shown.

The innerconical screen II has welded at its large end a flanged member I1. The outer conical screen I3 has welded at its enlarged end a bell-mouth I9, from which are struck inwardly directed tongues 2l. The flange moved to the left into engagement with the tongues 2| (compare Figs. 4 and 3). This predetermines the distance between screens II and I3, and the thickness of the mat I5.

The apex of the inner screen II is provided with a welded sheet-metal cap 23 on which is welded a stem 25 threaded to receive a nut 21. The stem passes loosely through an opening in a bracket 29 and carries a threaded thumbnut 3|. l

Welded on the apex of the outer conical screen I3 is a sheet-metal cap 33 against which the thumb-nut 3l bears when screwed to the right in Figs. 3 and 5. By this means, the screens II and I3 may be drawn together after a supply of the fibrous material I5 has been interposed between them until the ange I1 comes against the tongues 2I, thus gaging the thickness of the mat I5. This conical assembly is then slipped into the cylindric portion, in the absence of the brace 29, which at this time has been removed. The enlarged end of the cone 9 is slightly smaller in diameter than the inside of cylinder I, and therefore enters into the large end of the frustrum 3. The brace 29 is then fastened to the cylinder I after being made loosely to receive the pin 25 (Fig. 5). After the brace 29 has been fastened down, the nut 21 is turned against the brace 29 to force the conical assembly tightly into its position shown in Fig. 3. Since the base of the cone 9 is somewhat smaller than the cylinder I, it tends to Wedge into the enlarged end of the frusto-conical portion 3. l

The brace 29 consists of two horizontal bars 35 and a vertical bar 39 fastened to cylinder I at nuts 31 and supported at a pad 4 I.

At the upper side of the inlet opening 43 of cylinder I is a bracket 45 for removably supporting an inlet nozzle 41. This nozzle has a control I1 may be valve 49. The nozzle receives water from a suitable line under pressure and sprays it downstream as a. mist or fog upon the upper side of the cone 9, as indicated in Fig. 2. This Wets the excelsior or sisal mat I5, and excess water drips across the hollow downstream side of a cone, as indicated by the droplets in Fig. 2. The drops fall into the mat of the lower segment of the cone and are there absorbed for subsequent evaporation. Any additional excess, including that sprayed onto the walls of the cylinder I' is caught in the bottom of the cylinder I and re moved at a drain I, a partial enclosure 53 preventing exit of the Water through the air-inlet opening 43. A strainer 52 is used over drain 5I.

A fan 55 is supported at the plane of the small end of the frustrum 3 and at the inlet 51 of the cylinder 5, the tip circle of the blades barely clearing within the inlet 51. The blades are driven by a motor 59 supported on a bracket 5I, the latter being located in the frustrum 3. A motor access door is provided at 63. Thus the cylinder 5 constitutes an outlet nozzle for the fan 55` located at the small end of the frustrum 3. The length of this nozzle should preferably be at least equal to the diameter of the tip circle of the fan blades 55, so asto prevent air outside of the enclosure constituted by the nozzle 5 from circulating backward around the outer edge of the fan tip circle or through the central portion of the fan wheel, where the force of the air flow is small. In other words, this cylinder 5 permits enough nozzle eiect to let the air from the fan convert some of its kinetic energy into pressure energy at the outlet 65, thus at all points blocking the undesired back ilow. This construction in combination with the frustrum 3 reaching from the fan to the large end of the .cone 9 produces eicient slow air movement through the mat with a suitable velocity at the outlet 65.

The advantages of the conical form of evaporating mat pointing upstream are several. In the iirst place, this permits the large end of the screen to be near the fan, so that as air leaves the screen it has a minimum velocity and therefore no tendency to pick up and entrain droplets of moisture. After the air has left the screen .it accelerates in the tapering frustrum 3. By,

this time, it can no longer entrain droplets. The distance between the fan 55 and the base of the cone 9 is made enough to insure gradual acceleration Without water entrainment.

The conical form of mat, located upon a horizontal axis allows simple application of the spray Water on one side and the dripping function across the axis of the one to the other side for complete saturation through out of the fibers of the mat I5. The conical form also allows of a very simple adjustment about a horizontal axis by loosening the nut 21. Thus can be accomplished reverse of the top and bottom of the cone when this is desired. It is desired from time to time, because foreign material which is ltered out from the air and carried down from the top said of the mat may readily be washed out by placing this top side on the bottom, thus also exposing the fresh washed-out bottom at the top for a desirable period. The foreign material is then washed out of the bottom by reverse gravity ilow.

'I'he nozzle 41 is arranged adjacent to the apex of the cone 9 in the air stream and above said cone. This makes the natural ow of air through the cylinder I aid in distributing the spray over the entire length of the cone.

The velocity of the air through .the cone Is relatively low compared to the velocity of exit through the air nozzle 5 because of the larger size of the cylinder I with respect to the cylinder 5. This desirable low velocity is compensated for by the large superficial area of the conc which permits high-capacity at low velocity through the mat. The device compactly encloses a relatively large cubical content, thereby permitting a large capacity for its size. 'Ihe location of the cylinders I and 5 and conical portions 3 and 9 on horizontal axes also adapts the device for suspension from ceilings and the like, thus making best use of headroom without taking up floor space, and without providing special bases or the like. For example, the device has particular application to shoe factories, where floor space is at a premium and high humidifying capacity is necessary with absolute assurance that the air does not carry entrained moisture.

Exemplary dimensions are as follows:

Length of cylinder I, forty-four inches; length of frustum 3, fourteen inches; length of cylinder 5, twenty inches; diameter of cylinder I, thirty inches; diameter of cylinder 5, twenty and onehalf inches; length of cone 9 from base to tip, thirty-six and one-fourth inches; size of motor, 59, 1A; H. P. 180 watts are consumed at 1140 R. P. M., and 120 watts at 900 R. P. M. The capacity of a device of the above size is 3500 cu. ft. per minute of free air. This is for a condition of ingoing air at 15 F. dry bulb, and 58 F. wet bulb (34% relative humidity) and the outgoing air being 60 F. dry bulb and 59 F. wet bulb (94% relative humidity). 'I'hus this compact and simple machine is capable of raising the relative humidity 60%, at the rate of 3500 cu. ft. of air per minute, under the conditions described.

The evaporative effect of the device also makes it useful as an evaporative cooler.

In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results attained.

As many changes could be made in the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawing shall be interpreted as illustrative and not in a limiting sense.

I claim:

1. An evaporator comprising a relatively large cylinder and a relatively smaller cylinder joined by a conical reducing portion, all horizontally located to form a horizontal enclosure having an air inlet in the large cylinder and an air outlet in the small cylinder, a conical mat containing stiff but absorbent fibrous material and having its apex upstream in said large cylinder and its base supported by the large end of said reducing portion, said mat being mounted for rotary repositioning from time to time, means located on the upstream side of the mat for spraying enough water on the upper side of the conical mat for complete absorption and progression of excess to the lower side thereof for absorption, and means on the downstream side of said mat adapted to draw air through it.

2. An evaporator comprising a relatively large cylinder and a relatively smaller cylinder joined by a conical reducing portion, all horizontally located to form a horizontal enclosure having an Y air inlet in the large cylinder and an air outlet in the small cylinder, a conical mat containing stifl but absorbent brous material and having its apex upstream in said large cylinder and its base supported at the large end of said reducing portion, said mat being mounted for rotary repositioning from time to time, means for spraying water downstream in said large cylinder on the upper segment of the conical portion of the mat drip from said upper segment across the cone to its lower segment for absorption throughout both segments, and a propeller type fan rotating substantially at the junction between the small cylinder and the small end oi' the frustoconical portion, the tip circle of which fan is substantially the diameter ofsaid relatively small cylinder, and the length of said small cylinder being at least equal to the diameter of said tip circle to form a non-retum air nozzle, the axis of rotation of the fan and said cylinder and conical portions all being concentric.

3. An evaporator comprising a relatively large cylinder and a relatively smaller cylinder joined by a conical reducing portion, all horizontally located to form a horizontal enclosure having an air inlet in the largecylinder and an air outlet in the small cylinder, a conical mat holder having its apex upstream in said large cylinder and its base wedged into the large end of said frusto-ccnical portion, means for supporting the mat holder and forcing it into wedging engagement and adapted to permit rotation of the holder from time to time, means on the upstream side of the mat for spraying enough water on the top of the mat so that it soaks the top of the mat and drips across the inside of the mat to its bottom side for soaking, and a fan on the downstream side of the mat for drawing air therethrough, rotation of said holder effecting reversal of the water flow through the mat.

4. In an evaporator, a pair of open-mesh, rigid cones, one of which is smaller than the other, means for engaging the large ends of said cones to provide a predetermined spacing .between the cones, a mat packing means between said cones, screw tension means between the apexes of said cones, a housing surrounding said' cones and having a portion engaged by their assembled large ends, a bracket in said housing adjacent the apex portions of the assembled cones, and nut means on said screw tensioning member adapted by rotation to react against the brace'to hold the cone assembly in said housing.

5. An evaporator comprising a horizontal cylinder having an air inlet at one end and an air outlet at the other end, a conical member composed of absorbent mat material having an apex directed upstream in said cylinder with its base downstream, and quick-releasable means for holding said conical member in position which will permit of its rotation from time to time, and means for applying a spray of water to the upper segment only of the conical member in such an amount as to eiect movement across the cone to its lower segment for absorption, said rotation permitting positioning of the mat with respect to the spray means to reverse iiow across the mat.

6. An evaporator comprising a relatively large cylinder having an air inlet and an air outlet, a conical mat coaxial with said cylinder having its apex directed toward said inlet and its base adjacent to the outlet, a`water nozzle located to soak the top segment of the mat and to provide excess of water to drip to the bottom segment, a frustoconical reducing portion connected to said outlet and forming a seat for the base of said cone, means for forcing the cone against said seat and for loosening the cone from time to time for rotary reorientation, a relatively small cylinder attached to the small end of said frusto-conical portion and forming an air outlet nozzle, a bladed fan rotating substantially at the plane of the connection between the outlet air nozzle and the small end of said frusto-conical portion, and motor means for operating said fan mounted in said frusto-conical portion, the assembly of cylinders, frusto-conical portion and cones being concentric on a horizontal axis.

7. An evaporator comprising a cylinder having an air inlet at one end and a tapered air outlet at the other, a conical mat member in said cylinder having its apex upstream with respect to air flowing through said cylinder and having its base resting on said tapered air outlet, compression means on the apex of the mat member for mounting the mat member by pressing it against said outlet permitting its rotation when desired, a brace from said cylinder-against which said compression means reacts, and means for applying water to the upstream side of said cone,`said cylinder and cone being horizontally located,

whereby said water after application to the coneV may drip across the open downstream portion of the same to wet it entirely, any excess gravitating into the cylinder, and a drain from said cylinder.

FREDERICK L. BooK. 

